package com.bell.scansdcardfiles.util;

import java.io.File;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Created by bell on 17/10/11.
 */

public class FileUtil {

    /**
     * 格式化日期
     *
     * @param s
     * @return
     */
    public static String formatTime(long s) {
        if (s <= 0) {
            return null;
        }

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        return sdf.format(new Date(s));
    }

    /**
     * 返回byte的数据大小对应的文本
     *
     * @param size
     * @return
     */
    public static String getDataSize(long size) {
        DecimalFormat df = new DecimalFormat("####.00");
        if (size < 1024) {
            return size + " bytes";
        } else if (size < 1024 * 1024) {
            float kbsize = size / 1024f;
            return df.format(kbsize) + " KB";
        } else if (size < 1024 * 1024 * 1024) {
            float mbsize = size / 1024f / 1024f;
            return df.format(mbsize) + " MB";
        } else if (size < 1024 * 1024 * 1024 * 1024) {
            float gbsize = size / 1024f / 1024f / 1024f;
            return df.format(gbsize) + " GB";
        } else {
            return "size: error";
        }
    }

    /**
     * 递归删除目录下的所有文件及子目录下所有文件
     * @param dir 将要删除的文件目录
     * @return boolean Returns "true" if all deletions were successful.
     *                 If a deletion fails, the method stops attempting to
     *                 delete and returns "false".
     */
    public static boolean deleteDir(File dir) {
        if (dir.isDirectory()) {
            String[] children = dir.list();
            //递归删除目录中的子目录下
            for (int i=0; i<children.length; i++) {
                boolean success = deleteDir(new File(dir, children[i]));
                if (!success) {
                    return false;
                }
            }
        }
        // 目录此时为空，可以删除
        return dir.delete();
    }

}